Turbine Engine Transmission Gutter

ABSTRACT

A turbine engine case defines a centerline and a gaspath within the engine case. A fan is coupled to a fan shaft. A transmission couples the shaft to the fan shaft to drive the fan and comprises a gear system. A gutter system is positioned to capture lubricating fluid slung from the gear system. The gutter system includes a gutter extending partially circumferentially about the centerline having a first circumferential end edge. An inlet channel has an inlet at the gutter first circumferential end edge and locally radially outboard of the gutter. At least one vane is spaced apart from the gutter first circumferential end edge.

BACKGROUND

The disclosure relates to gas turbine engines. More particularly, thedisclosure relates to lubrication of fan drive gear systems in gasturbine engines.

Typical gas turbine engines have one or more turbine sections drivingone or more compressor sections. The one or more turbine sections mayalso drive a fan. Many engines have an equal number of turbine andcompressor sections (typically two). An exemplary such engine involves alow pressure turbine (LPT) section coupled to a low pressure compressor(LPC) section to drive the low pressure compressor section. Similarly, ahigh pressure turbine (HPT) section is coupled to a high pressurecompressor (HPC) section to drive the high pressure compressor. In suchsituations, the fan is typically driven by the LPT. The rotatingcomponents of the LPT and LPC are commonly designated a low pressurespool while the rotating components of the HPT and HPC are commonlydesignated a high pressure spool. In such or other engines, the fan maybe driven via a transmission (typically a gear reduction so that the fanis driven at a lower rotational speed than its driving spool).

An exemplary transmission is a fan drive gear system (FDGS) formed as anepicyclic geared transmission. With a typical fan at the front of anengine, the transmission is typically positioned between the fan and theLPC.

For lubricating the transmission, one or more supply pumps supplylubricating liquid (e.g., oil) to the fan drive gear system and one ormore scavenge pumps typically scavenge the lubricating liquid from thefan drive gear system. If the scavenged lubricating liquid is highlyaerated, a small scavenge pump may not be suitable to scavenge thelubricating liquid from the fan drive gear system, thus causing flow toback up and potentially lead to oil leakage, excess heat generation, andlow oil quantity alarms. If a larger scavenge pump is used, that can addweight and take additional space, which is undesirable in systems whereweight and space are a premium.

Exemplary lubrication systems, components, and methods of use aredisclosed in US Pregrant Publications: 2008/0116010A1 entitled“Lubrication System with Tolerance for Reduced Gravity”; 2010/0212281A1entitled “Auxiliary Pump System for Fan Drive Gear System”;2010/0294597A1 entitled “Windmill and Zero Gravity Lubrication System”;2010/0294371A1 entitled “Gravity Operated Valve”; and 2011/0108360A1entitled “Oil Capture and Bypass System”; and 2008/0116009A1 entitled“Lubrication System With Extended Emergency Operability”; and U.S. Ser.No. 13/165,967, filed Jun. 22, 2011 entitled “Oil Bypass ChannelDeaerator for a Geared Turbofan Engine”. The foregoing publications andapplication are incorporated by reference in their entireties herein asif set forth at length.

SUMMARY

One aspect of the disclosure involves a gutter system for capturinglubricating fluid slung from a gear system. The gutter system includes agutter extending partially circumferentially about a centerline having afirst circumferential end edge. An inlet channel has an inlet at thegutter first circumferential end edge and locally radially outboard ofthe gutter. At least one vane is spaced apart from the gutter firstcircumferential end edge.

In additional or alternative embodiments of any of the foregoingembodiments, the at least one vane may be exactly two vanes. The atleast one vane may be at least two vanes. The at least two vanes may bepositioned with a leading vane and a trailing vane. The leading vane mayhave an outboard edge and the trailing vane may have an outboard edgeradially recessed relative to the leading vane outboard edge. Thetrailing vane may be spaced apart from both the leading vane and awayfrom the scroll wall. The trailing vane may be spaced apart from theleading vane and the gutter first circumferential end/edge by 1-4 timesa thickness of the trailing vane.

In additional or alternative embodiments of any of the foregoingembodiments, the at least one vane may be positioned with a chordoriented with a component from an outboard edge to an inboard edgecircumferentially in the same direction as an inlet flow direction.

In additional or alternative embodiments of any of the foregoingembodiments the gutter system may be installed in an engine. An enginecase defines a centerline and a gaspath within the engine case. A fan iscoupled to a fan shaft. A transmission couples the shaft to the fanshaft to drive the fan and comprises a gear system. The gutter system ispositioned to capture lubricating fluid slung from the gear system.

In additional or alternative embodiments of any of the foregoingembodiments, the transmission may be an epicyclic transmission.

In additional or alternative embodiments of any of the foregoingembodiments, the gutter may comprise a flange. The engine may comprisean auxiliary lubricant tank. An outlet of the inlet channel to theauxiliary lubricant tank may be along the flange.

In additional or alternative embodiments of any of the foregoingembodiments, the at least one vane may be oriented to inwardly deflect atangential flow passing along a leading face without tangentiallyreversing the flow.

In additional or alternative embodiments of any of the foregoingembodiments, the engine may have at least one compressor section, acombustor, and at least one turbine section. The shaft may be coupled tothe turbine section. The at least one compressor section may comprise ahigh pressure compressor section and a low pressure compressor section.The at least one turbine section may comprise a high pressure turbinesection and a low pressure turbine section. The shaft may be a lowpressure turbine shaft coupling the low pressure turbine section to thelow pressure compressor section. A high pressure shaft may couple thehigh pressure turbine section to the high pressure compressor section.

Another aspect of the disclosure involves a method for operating any ofthe foregoing embodiments. The lubricating fluid is flung with atangential/circumferential velocity component in a first direction. Aportion of the flung lubricating fluid flows in the first directionalong an inboard surface of the gutter. A portion of the lubricatingfluid flowing along the gutter inboard surface passes into the inlet ofthe inlet channel.

In additional or alternative embodiments of any of the foregoingembodiments, as the portion of the lubricating fluid flowing along thegutter inboard surface passes into the inlet of the inlet channel afirst of the at least one vane diverts a relatively air-rich portionaway from the inlet and then a second of the at least one vane diverts arelatively air-rich portion of the remainder away from the inlet.

In additional or alternative embodiments of any of the foregoingembodiments, as the portion of the lubricating fluid flowing along thegutter inboard surface passes into the inlet of the inlet channel, theat least one vane diverts a relatively air-rich portion away from theinlet.

Another aspect of the disclosure involves a gutter system for capturinglubricating fluid slung from a gear system. The gutter system includes agutter extending partially circumferentially about a centerline having afirst circumferential end edge. An inlet channel has an inlet at thegutter first circumferential end edge and locally radially outboard ofthe gutter. Means are circumferentially ahead of the firstcircumferential end edge for diverting gas from a tangential flow of theslung lubricating fluid.

In additional or alternative embodiments of any of the foregoingembodiments, the means comprises at least one vane positioned to diverta relatively gas-rich inboard portion of the tangential flow from arelatively gas-poor outboard portion.

In additional or alternative embodiments of any of the foregoingembodiments, the vane is positioned to pass said relatively gas-pooroutboard portion to the inlet where a relatively gas-rich portionthereof is diverted by the first circumferential end edge so that arelatively gas-poor portion thereof is passed through the inlet.

In additional or alternative embodiments of any of the foregoingembodiments, the gutter system may be installed in an engine. An enginecase defines a centerline and a gaspath within the engine case. A fan iscoupled to a fan shaft. A transmission couples the shaft to the fanshaft to drive the fan and comprises a gear system. The gutter system ispositioned to capture lubricating fluid slung from the gear system.

The details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional side view of a gas turbine enginewith a fan drive gear system.

FIG. 2 is a schematic view of a pump system for use in the gas turbineengine of FIG. 1.

FIG. 3 is a partial perspective view of an oil capture and bypass systemwith a portion cut away above line 3-3 in FIG. 4.

FIG. 4 is a partial sectional elevation view of an upper portion of theoil capture and bypass system taken along line 4-4 in FIG. 3.

FIG. 5 is a partial sectional elevation view of a lower portion of theoil capture and bypass system taken along line 5-5 in FIG. 1.

FIG. 6 is a partial forward-looking transverse cutaway view of a secondoil capture and bypass system.

FIG. 6A is an enlarged view on an inlet region of the system of FIG. 6.

FIG. 7 is a longitudinal cutaway view of the system of FIG. 6 takenalong line 7-7 of FIG. 6.

FIG. 8 is an isolated view of the gutter of the system of FIG. 6.

FIG. 9 is a partial cutaway view of the gutter taken along line 9-9 ofFIG. 6.

FIG. 10 is a partial cutaway view of the gutter taken along line 10-10of FIG. 6.

FIG. 11 is a partial cutaway view of the gutter taken along line 11-11of FIG. 6.

FIG. 12 is a partial cutaway view of the gutter taken along line 12-12of FIG. 6.

Various of the drawings reflect artifacts of computer generation. Forexample, although sectioning planes are shown in FIG. 6 for each ofFIGS. 9-11, the view is not necessarily normal thereto (rendering itmore of a cutaway than a section). Additionally, some background detailsare suppressed.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

FIG. 1 is a schematic cross-sectional side view of gas turbine engine10. Gas turbine engine 10 includes low pressure spool 12 (which includeslow pressure compressor (LPC) 14 and low pressure turbine (LPT) 16connected by low pressure shaft 18), high pressure spool 20 (whichincludes high pressure compressor (HPC) 22 and high pressure turbine(HPT) 24 connected by high pressure shaft 26), combustor 28, nacelle 30,fan 32, fan shaft 34, and fan drive gear system 36 (which includes stargear 38, ring gear 40, and sun gear 42). Low pressure spool 12, highpressure spool 20, fan shaft 34, and fan drive gear system 36 all rotatesubstantially around centerline axis C_(L) defined by/within the enginemain case. The LPC, HPC, combustor, HPT, and LPT are sequentially alonga core gaspath through the engine main case. The fan directs an inletflow to be split between the gaspath and a bypass flowpath surroundingthe main case.

The general construction and operation of gas turbine engines iswell-known in the art, and therefore detailed discussion here isunnecessary. However, a more detailed understanding of fan drive gearsystem 36 can be helpful. As shown in FIG. 1, low pressure spool 12 iscoupled to fan shaft 34 via fan drive gear system 36. In the illustratedembodiment, fan drive gear system 36 is a “star gear system”. Sun gear42 is attached to and rotates with low pressure shaft 18. Ring gear 40is rigidly connected to fan shaft 34 which turns at the same speed asfan 32. Star gear 38 is coupled between sun gear 42 and ring gear 40such that star gear 38 revolves about its axis, when sun gear 42rotates. When low pressure spool 12 rotates, fan drive gear system 36causes fan shaft 34 to rotate at a slower rotational velocity than thatof low pressure spool 12. This allows fan 32 and low pressure spool 12to rotate at different speeds for improved operation of both fan 32 andlow pressure spool 12. In an alternative embodiment, fan drive gearsystem 36 can be a “planetary gear system”. In a planetary gear system,ring gear 40 is fixed and fan shaft 34 is attached to a carrier (notshown) that carries star gear 38 (also called a planet gear). Star gear38 orbits about sun gear 42 as it spins between sun gear 42 and ringgear 40.

Pump 44 is coupled to and is driven by fan shaft 34 via pump gear 46such that pump 44 can operate whenever fan shaft 34 is rotating. Pump 44supplies a lubricating liquid, such as oil, to lubricate components suchas gears and bearings of fan drive gear system 36. Fan drive gear system36 benefits from a relatively continuous supply of lubricating liquidwhenever fan shaft 34 is rotating. In an alternative embodiment, pump 44can be an electrically driven oil pump. At least some of the lubricatingliquid supplied to fan drive gear system 36 drains to sump 48 and iseventually pumped back through pump 44. Gutter system 49 is positionedcircumferentially around fan drive gear system 36 to catch and collect aportion of the lubricating liquid that drips or is slung off fan drivegear system 36, as further explained below.

FIG. 2 is a schematic view of pump system 50. Pump system 50 includesbearing compartment 52 having a compartment cavity that contains fandrive gear system 36 (including bearings 54), auxiliary pump 44, guttersystem 49 (including gutter 56 and passage 90), auxiliary 3 reservoir58, and first shuttle valve 60. Pump system 50 also includes secondshuttle valve 62, main reservoir 64, main pump 66, and scavenge pump 67positioned outside of bearing compartment 52. Passages 68, 70, 72, 74,76, 78, 80, 82, 84, 86, 88, and 90 connect the various components asillustrated and as further described, below.

As fan drive gear system 36 spins, lubricating liquid drips or is slungoff fan drive gear system 36 into bearing compartment 52 in differentdirections, illustrated by arrows a. A portion of that liquid is caughtand collected by gutter 56 and funneled to auxiliary reservoir 58.During normal operating conditions, auxiliary reservoir 58 is keptsubstantially full of liquid for later use. In one embodiment, auxiliaryreservoir 58 contains enough liquid to provide adequate lubrication forfan drive gear system 36 for a specified amount of time. Liquid inexcess of that required by auxiliary reservoir 58 is delivered to bypasspassage 90 and ultimately to main scavenge passage 86. Gutter system 49has a series of holes (illustrated in FIG. 5) that allows lubricatingliquid to pass in directions illustrated by arrows γ and β toward wall92 of bearing compartment 52.

Gutter 56 does not collect all liquid leaving fan drive gear system 36.The remaining liquid that is not collected by gutter 56 falls to sump48, which is an open-top reservoir at a bottom of bearing compartment52. Bearing compartment 52 can be sealed to reduce liquid flow out ofbearing compartment 52, except through designated passages as hereindescribed.

Second shuttle valve 62 is fluidically connected to auxiliary pump 44via passage 76, to main pump 66 via passage 78, to bearings 54 viapassage 80, and to main reservoir 64 via passages 82 and 88. Secondshuttle valve 62 selectively directs fluid flow from auxiliary pump 44or main pump 66 to bearings 54. Main reservoir 64 is further connectedto main pump 66 through passage 84. Scavenge pump 67 is connected tosump 48 via main scavenge passage 86 and to main reservoir 64 viapassage 88. Scavenge pump 67 pumps a portion of the liquid in sump 48 tomain reservoir 64 for use by main pump 66. (See US Pregrant PublicationNo. 2010/0294597 entitled “Windmill and Zero Gravity Lubrication System”published Nov. 25, 2010 and assigned to the same assignee as thisapplication for a more detailed description of the function of secondshuttle valve 62).

First shuttle valve 60 is fluidically connected to auxiliary reservoir58 via passage 68, to sump 48 via passage 70, to auxiliary pump 44 viapassage 72, and again to sump 48 via passage 74. As part of pump system50, first shuttle valve 60 and second shuttle valve 62 work together asa valve system. This valve system directs lubricating liquid to bearings54 from one of sump 48, auxiliary reservoir 58, or main reservoir 64.When engine operating conditions prevent main pump 66 from supplyingadequate liquid, second shuttle valve 62 switches from main pump 66 toauxiliary pump 44. Switching to auxiliary pump 44 can be beneficial ifit has an adequate supply of liquid from first shuttle valve 60 duringall gravity conditions. (See US Pregrant Publication No. 2010/0294371entitled “Gravity Operated Valve” published Nov. 25, 2010 and assignedto the same assignee as this application for a more detailed descriptionof the function of first shuttle valve 60).

FIG. 3 is a partial perspective view of oil capture and bypass system100. In order to show greater detail in FIG. 3, a portion of oil captureand bypass system 100 has been cut away and removed above line 3-3 inFIG. 4. Oil capture and bypass system 100 includes gutter 56, auxiliaryreservoir 58, and bypass passage 90. In the illustrated embodiment,auxiliary reservoir 58 is integrally formed with, and exists completelyinside, bearing support 102. Bearing support 102 supports No. 1 and No.1.5 bearings (not shown) of fan shaft 34 (shown in FIG. 1). Bearingsupport 102 includes sub-supports 104 that are positioned insideauxiliary reservoir 58, without substantially restricting flow withinauxiliary reservoir 58. Auxiliary reservoir 58 has reservoir inlet 106positioned relatively near reservoir outlet 108.

Gutter 56 is positioned radially outward from centerline axis C_(L)(shown in FIG. 1) and extends circumferentially around fan drive gearsystem 36 (shown in FIGS. 1 and 2) for capturing lubricating liquidslung from fan drive gear system 36. A portion of gutter 56 is cut awayto show flange 110. Flange 110 is connected to ring gear 40 (shown inFIGS. 1 and 2). The lubricating liquid from fan drive gear system 36 isslung through holes 112 in flange 110 into gutter 56. The lubricatingliquid then slides around gutter 56 until it gets to gutter exit channel114.

When auxiliary reservoir 58 is substantially empty, lubricating liquidfrom gutter 56 fills auxiliary reservoir 58. When auxiliary reservoir 58is substantially full, excess lubricating liquid hits a “wall” of liquidand is then forced through reservoir outlet 108 into bypass passage 90with the aid of diverter 115 which acts as a scoop to capture the excessliquid. Flow arrow F₁ generally illustrates the direction of flowthrough reservoir inlet 106. Flow arrow F₂ generally illustrates thedirection of flow through reservoir outlet 108.

In the illustrated embodiment, gutter 56 and bypass passage 90 areintegrally formed as gutter system 49 and can be cast as a single piece.Exterior wall 118 of gutter 56 is essentially a shared wall betweengutter 56 and bypass passage 90. Because gutter system 49 abut directlyto auxiliary reservoir 58, the connections can be made without aseparate intervening connector pipe and without the losses in flowenergy associated therewith. This configuration allows gutter 56 andauxiliary reservoir 58 to be substantially side-by-side.

FIG. 4 is a partial sectional elevation view of a portion of oil captureand bypass system 100 taken along line 4-4 in FIG. 3. The view of FIG. 4is from the aft of gas turbine engine (shown in FIG. 1) looking forwardalong centerline axis C_(L). Gutter inner radius R1 extends fromcenterline axis C_(L) to an inner diameter of gutter 56. Gutter outerradius R₂ extends from centerline axis C_(L) to exterior wall 118 at anouter diameter of gutter 56. Bypass passage inner radius R₃ extends fromcenterline axis C_(L) to an inner diameter of bypass passage 90. Bypasspassage outer radius R₄ extends from centerline axis C_(L) to exteriorwall 116 at an outer diameter of bypass passage 90. Bypass passage innerradius R₃ is about the same as gutter inner radius R. There is a gapbetween exterior wall 116 and exterior wall 118 such that a portion ofbypass passage 90 is radially outward from gutter 56 but other portionsof bypass passage 90 are on both sides of gutter 56, having the sameradial distance from centerline axis C_(L) as a portion of gutter 56.Auxiliary reservoir (shown in FIG. 3) is obscured in FIG. 4; however,the radius from centerline axis C_(L) to exterior wall 120 (shown inFIG. 3) of auxiliary reservoir 58 is about the same as R2. Thisconfiguration allows oil capture and bypass system 100 to have arelatively small maximum radius. The respective radii of the variouselements need not, however, be precisely as illustrated.

FIG. 5 is a partial sectional elevation view of a lower portion of oilcapture and bypass system 100 taken along line 5-5 in FIG. 1. FIG. 5shows fan drive gear system 36, which is surrounded by gutter system 49of oil capture and bypass system 100, which is surrounded by wall 92 ofbearing compartment 52, which is surrounded by a plurality of inletguide vane blades 130 of inlet guide vane system 132.

Bypass passage 90 is bounded by wall 116 and wall 118 and terminates atmetered restriction end 134. Aerated lubricating liquid flows throughbypass passage 90 in a clockwise direction toward metered restrictionend 134. Metered restriction end 134 has hole 136 to drain lubricatingliquid after engine shut down in a direction illustrated by arrow β.Wall 116 also includes a plurality of holes 138. Holes 138 allow aeratedlubricating liquid to pass through in directions illustrated by arrows yand contact wall 92 of bearing compartment 52. The action of beingsquirted from holes 138 against wall 92 causes aerated lubricatingliquid to substantially deaerate. Deaerated lubricating liquid fromholes 138 continue to flow in a clockwise direction through a spacebetween gutter system 49 and wall 92 to main scavenge passage 86 to bescavenged by scavenge pump 67 (shown in FIG. 2). Scavenge pump 67creates a suction to pull lubricating liquid through main scavengepassage 86 and return it to main reservoir 64 (shown in FIG. 2). Byremoving air from the lubricating liquid, scavenge pump 67 can pump thelubricating liquid more efficiently.

In the illustrated embodiment, each of holes 138 extend through wall 116of bypass passage 90 at locations vertically higher than the lowestposition of wall 116. Wall 116 of bypass passage 90 curvescircumferentially with respect to centerline axis C_(L) (shown in FIGS.1 and 4). This curvature forces aerated lubricating liquid travelingclockwise through bypass passage 90 to curve. This orientation alsoforces a substantial amount of lubricating liquid to pass through holes138 and be deaerated upon impact with wall 92. Because the lubricatingliquid has a relatively high velocity when it strikes wall 92, theamount of air in the aerated lubricating liquid is decreased.

FIG. 6 shows a revised gutter system 200 which may be otherwise similarto the gutter system described above and used in place thereof.

In the forward-looking view of FIG. 6, the fan shaft assembly 202rotates in a clockwise direction 520.

FIG. 7 shows the fan shaft assembly 202 as including a forward hub/scoop204 at the front of the fan drive gear system coupling the ring assembly206 to the main fan shaft section 208. The ring gear assembly 206comprises a forward half 210 and an aft half 212 each having a radiallyinboard gear-engaging toothed portion and a radially outboard flange214, 216. The flanges 214, 216 are sandwiched between and bolted to aflange 218 of the hub 204 forward and a flange 220 of an aft oil scoop222. Holes 226 (formed by mated complementary channels in the facingsurfaces of the flanges 214 and 216) sling oil flows F₃ outward into theinterior 230 of the gutter channel. With the ring gear rotating in thedirection 520 in FIG. 6 the flow F₃ is slung with a tangential componentin that direction 520. The slung flow encounters the inboard surface 240of the outer wall along the channel 230 and forms a circumferential flowF₄ (FIG. 6A).

Eventually the flow F₄ reaches an inlet 248 (FIG. 8) to an inlet channel250. FIG. 8 is an isolated view of the gutter assembly showing the inlet248 to the inlet channel 250. FIG. 8 also shows an outer cap 252 of theinlet channel. The inlet channel 250 diverts forward and has a forwardlateral wall 254 and an aft lateral wall 256. An inlet channel outlet258 is along a gutter outer/outboard flange 260. Similarly, the bypasschannel 261 has an inlet 262 along the flange 260 and has a forward wall264 and an aft wall 266 and a cap 268. The bypass channel extendscircumferentially to an outlet nozzle 270 generally near the bottom ofthe gutter. FIG. 8 also shows an interior/inboard flange 272 of thegutter.

As the flow F₄ approaches the inlet 248, it encounters a pair ofsplitter vanes 280, 282 (FIG. 6A). Each splitter vane has an outboardedge 284, 286 and an inboard edge 288, 290. The exemplary vanes alsohave a leading surface 292, 294 generally facing the flow F₄ and atrailing surface 296, 298. FIGS. 9-12 also show the vanes extendinggenerally longitudinally from a forward end at forward wall 300 of theinlet channel to an aft end at an aft wall 302 of the inlet channel.Turning to FIG. 6A, the first vane 280, outboard edge 284 is spacedapart from the inner surface 240 along the channel scroll portion 320 ofthe outer wall by a gap having a height H. The channel scroll terminatescircumferentially at an inboard weld 322 to the inlet cap 252 attachedto an outboard surface of the channel scroll. Various weld fillet edgesare labeled 323.

The exemplary outboard edge 286 of the second vane 282 is slightlyradially recessed relative to the outboard edge 284 so that a height H₂between the edge 286 and a projection of the surface 240 is greater thanH.

Due to centrifugal action, the flow F₄ is radially stratified with arelatively lubricant(oil)-rich strata 340 near the wall progressivelytransitioning through a more gas-rich (air-rich/oil-poor) strata 342radially inboard thereof. The vane 280 is positioned so that theoutboard edge 284 falls between these strata so that the air-richportion F₄′ is diverted radially inboard by the vane. In the exemplaryembodiment, this diversion preserves a tangential component of thediverted flow in the direction 520 allowing a smooth continuation of thetangential flow F₄ along the surface 240 along the main spliter 352.Thus, the exemplary leading surface 292 and a chord between the leadingedge 284 and trailing edge 288 are oriented generally with a slightradially inward component (rather than radially outward component)facing the oncoming tangential flow. This is contrasted with ahypothetical alternative diverting the redirected flow back opposite thedirection 520.

Diversion of the relatively air-rich portion F₄′ leaves a more oil-richportion F₄″ to pass circumferentially past the first vane 280 outboardthereof. Yet a further portion F₄″′ will pass radially inward betweenthe vanes. This further portion F₄″′ will join with the flow F₄″″. FIG.6A shows this further portion F₄″′ as flowing relatively smoothly nearthe leading surface 294 of the second vane but near the trailing surface296 of the first vane there will be recirculation in a zone 360. Therecirculation zone 360 slows the oil/air mixture which allows the air toseparate easier from the oil/air mixture and the concentrated oil of themixture to continue above (outboard of) the first vane onto the secondvane and into the inlet channel. The air-majority mixture flow continuesalong the vane and reunites with the flow F₄′ and F₄. Flow F₄″″ passesbetween the trailing surface 298 of the second vane and the leading edge330 of a main splitter portion 352 of the gutter channel (edge 330forming a first circumferential end edge of the gutter). A recirculationzone 362 is similarly behind the second vane and affects the flowpassing behind the second vane. Thus, the recirculation zone 362facilitates the air rich portion F″″ separating from a remainingoil-rich portion. The remaining oil-rich portion of the flow then passesinto and through the inlet channel.

In the exemplary implementation, the relatively greater spacing H₂versus H₁ is associated with a slowing of the oil-rich flow. Thepresence of the first vane tends to slow the flow passing beyond it and,therefore, increase the radial layer thickness of the oil-rich flow.Accordingly, the second vane is spaced farther away from the surface 240(or its projection) to maintain a similarly selective diversion ofair-rich flow.

Manufacture of the gutter may be by generally conventional techniques.For example, an initial precursor may be formed by casting or a rapidprototyping method (e.g., direct metal laser sintering (DMLS)). Theprecursor may include the inlet and bypass channels (absent caps),scavenge baffle, aft baffle holes, vanes, and bypass channel holes. Theprecursor may then be machined to form or refine features such as theflange and bushing holes. After machining, caps (e.g., pre-made bymachining or laser cutting) may be welded in place.

One alternative would be to have a fully fabricated part with amultitude of individual pieces machined and welded together. A potentialcombination would be to have the main body and channel cast and thenweld machined caps onto the channel and then either have the vanes castin or machined then welded.

The exemplary cross-sectional profiles of the vanes are shown asslightly eccentric elongated hexagons. Alternative cross-sections may beoval or elliptical, trapezoidal, or airfoil shaped. There may be more orfewer than two such features and more complex features might beprovided.

One or more embodiments have been described. Nevertheless, it will beunderstood that various modifications may be made. For example, whenimplemented in the reengineering of a baseline engine, details of thebaseline may influence details of any particular implementation.Accordingly, other embodiments are within the scope of the followingclaims.

1. A gutter system for capturing lubricating fluid slung from a gearsystem comprising: a gutter extending partially circumferentially abouta centerline and having a gutter first circumferential end edge; aninlet channel having an inlet at the gutter first circumferential endedge and locally radially outboard of the gutter; and at least one vanespaced apart from the gutter first circumferential end edge.
 2. Thegutter system of claim 1 wherein: the at least one vane is exactly twovanes.
 3. The gutter system of claim 1 wherein: the at least one vane isat least two vanes.
 4. The gutter system of claim 3 wherein: the atleast two vanes are positioned with a leading vane and a trailing vane,the leading vane having an outboard edge and the trailing vane having anoutboard edge radially recessed relative to the leading vane outboardedge.
 5. The gutter system of claim 4 wherein: the trailing vane isspaced apart from both the leading vane and away from the scroll wall.6. The gutter system of claim 4 wherein: the leading vane and trailingvane are spaced apart from each other and the gutter firstcircumferential end edge by 1-4 times a thickness of the trailing vane.7. The gutter system of claim 1 wherein: the at least one vane ispositioned with a chord oriented with a component from an outboard edgeto an inboard edge circumferentially in the same direction as an inletflow direction.
 8. An engine comprising: an engine case, the engine casedefining a centerline and a gaspath within the engine case; a shaft; afan coupled to a fan shaft; a transmission coupling the shaft to the fanshaft to drive the fan and comprising a gear system; and the guttersystem of claim 1 positioned to capture lubricating fluid slung from thegear system.
 9. The engine of claim 8 wherein: the transmission is anepicyclic transmission.
 10. The engine of claim 8 wherein: the guttercomprises a flange; the engine comprises an auxiliary lubricant tank;and an outlet of the inlet channel to the auxiliary lubricant tank isalong the flange.
 11. The engine of claim 8 wherein: the at least onevane is oriented to inwardly deflect a tangential flow passing along aleading face without tangentially reversing the flow.
 12. The engine ofclaim 8 wherein: the engine has at least one compressor section, acombustor, and at least one turbine section; and the shaft is coupled tothe turbine section.
 13. The engine of claim 12 wherein: the at leastone compressor section comprises a high pressure compressor section anda low pressure compressor section; the at least one turbine sectioncomprises a high pressure turbine section and a low pressure turbinesection; the shaft is a low pressure turbine shaft coupling the lowpressure turbine section to the low pressure compressor section; and ahigh pressure shaft couples the high pressure turbine section to thehigh pressure compressor section.
 14. A method for operating the guttersystem of claim 1 wherein: the lubricating fluid is flung with atangential/circumferential velocity component in a first direction; aportion of the flung lubricating fluid flows in the first directionalong an inboard surface of the gutter; and a portion of the lubricatingfluid flowing along the gutter inboard surface passes into the inlet ofthe inlet channel.
 15. The method of claim 14 wherein: as the portion ofthe lubricating fluid flowing along the gutter inboard surface passesinto the inlet of the inlet channel the at least one vane diverts arelatively air-rich portion away from the inlet.
 16. The method of claim14 wherein: as the portion of the lubricating fluid flowing along thegutter inboard surface passes into the inlet of the inlet channel afirst of the at least one vane diverts a relatively air-rich portionaway from the inlet and then a second of the at least one vane diverts arelatively air-rich portion of the remainder away from the inlet.
 17. Agutter system for capturing lubricating fluid slung from a gear systemcomprising: a gutter extending partially circumferentially about acenterline and having a first circumferential end edge; an inlet channelhaving an inlet at the gutter first circumferential end edge and locallyradially outboard of the gutter; and means circumferentially ahead ofthe first circumferential end edge for diverting gas from a tangentialflow of the slung lubricating fluid.
 18. The gutter system of claim 17wherein: the means comprises at least one vane positioned to divert arelatively gas-rich inboard portion of the tangential flow from arelatively gas-poor outboard portion.
 19. The gutter system of claim 17wherein: the vane is positioned to pass said relatively gas-pooroutboard portion to the inlet where a relatively gas-rich portionthereof is diverted by the first circumferential end edge so that arelatively gas-poor portion thereof is passed through the inlet.
 20. Anengine comprising; the gutter system of claim 17; an engine case, theengine case defining a centerline and a gaspath within the engine case;a shaft; a fan coupled to a fan shaft; and a transmission coupling theshaft to the fan shaft to drive the fan and comprising a gear system.